1. Field of the Invention
The present invention relates to radio frequency (RF) transponders such as radio frequency identification (RFID) transponders, and in particular to a method and system for providing a RFID transponder having a fabric antenna.
2. Description of the Related Art
RFID systems are useful in a wide variety of applications, including, for example, security access, retail automation, inventory control, personnel identification, and manufacturing automation. RFID systems typically include an RFID transponder (hereinafter, an RF tag) having a semiconductor memory and an antenna, and an RFID interrogator comprising a transmitter-receiver unit for querying the RF tag via a wireless communication link. The RF tag detects the interrogating signal and transmits an encoded response signal to the interrogator. RF tags may be active or passive. An active RF tag includes an internal battery source to operate the active RF tag""s associated electronics, whereas a passive RF tag does not have an internal power supply.
An advantage provided by RFID systems is that the RF tags are readable at distances away from the interrogator. Another advantage is that the RF tag may be obscured from view and attached to a product or person in a hidden location. The RF tags may be hidden for a variety of reasons, including but not limited to, security, aesthetics, and manufacturing costs concerns. For these and other reasons, it is desirable to embody the RF tags in a very small form factor. Due to advances in electronics miniaturization, form factors on the scale of coins are possible. Accordingly, RF tags may be embedded in garment tags, product tags, and clothing.
A limiting factor in the manufacture of RF tags however is the size of the RF tag""s built-in antenna. RF tags typically include an antenna formed on a substrate and electrically connected to the RF tag""s electronic components. The built-in antenna permits detection of the interrogator signal and remote reading of the encoded signal from the RF tag within a prescribed distance (i.e., a xe2x80x9creading zonexe2x80x9d) of the RF tag.
Various antenna configurations are known to those skilled in the art, such as, for example, a dipole antenna. A dipole antenna should typically have a physical length approximately one-half wavelength (xcex/2) of the RF tag""s operating frequency. While the length of this type of antenna may be short for the operating frequency of an RF tag (e.g., 7 cm long), it is still larger than many desired RF tag form factors.
Moreover, the use of a larger antenna can be employed to extend the reading zone of the RF tag. However, including the larger antenna in the RF tag has the undesired effect of increasing the minimum size of the RF tag package.
Accordingly, there exists a need to overcome the size constraints imposed on the RF tag antenna by the size limitation of the RF tag""s housing or for factor.
It is an object of the present teachings to provide an antenna for an RF tag that overcomes the size limitations imposed by the housing of the RF tag.
It is another object of the present teachings to provide an RF tag having an antenna enabling improved detection and transmission of signals.
In accordance with the present teachings, an RF tag, including an RF tag having a small form factor, includes a housing, an RF integrated circuit enclosed in the housing, and a fabric antenna coupled to said RF integrated circuit and located outside of the housing. Further, a method of fabricating an RF tag is disclosed wherein the method includes the steps of enclosing an RF integrated circuit in a housing, forming a fabric antenna, and coupling the fabric antenna to the RF integrated circuit.
The above and other objects, advantages, and benefits of the present invention will be understood by reference to following detailed description and appended sheets of drawings.